A senior Afghan officer has shot dead eight American troops and a civilian before being killed himself at Kabul airport.
Relatives said Ahmad Gull, a veteran air force pilot, was not connected with terrorism but had been suffering from personal and money problems recently.
The killing of the air force trainers and advisers was the deadliest episode to date of an Afghan turning against his coalition partners.
The shooting, in which five Afghan soldiers were injured, occurred in an operations room of the Afghan Air Corps at Kabul airport.
"Suddenly, in the middle of the meeting, shooting started," said an Afghan Air Corps spokesman. "After the shooting started, we saw a number of Afghan army officers and soldiers running out of the building. Some were even throwing themselves out of the windows to get away."
Gull's brother Dr Mohammad Hassan Sahibi said he had been battling financial troubles and insisted he had no ties to insurgents.
"He was 48 years old," Mr Sahibi said. "He served his country for years. He loved his people and his country. He had no link with Taliban or al Qaida. He was under economic pressures and recently he sold his house. He was going through a very difficult period of time in his life."
It is the seventh time so far this year that members of the Afghan security forces, or insurgents impersonating them, have killed coalition soldiers or members of the Afghan security forces.
The Taliban claimed responsibility for the attack and claimed said the gunman was impersonating an army officer.
However a defence ministry spokesman denied any terrorist link, saying: "An argument happened between him and the foreigners and we have to investigate that."